Dental press



July 2.9, 1947.l J. c. sl-mRRocKl ErAl. 2,424,906

DENTAL PRESS Filed May 3, 1946 Patented July 29, 1947 DENTAL PRESS James C. Sharrock, Birmingham, Ala., and John A. Sheeley, Stamford; Conn.

ApplicationMay 3, 1946, Serial No. 666,862

Our present invention relates toan improvement in presses and more particularly to a press which is especially adapted for use in dental laboratories in the molding of dentures, and has for an object the provision of a press of the character designated which shall be simple and sturdy of desi-gn, reliable in operation, and readily adjustable for use with various materials and types of molding flasks.

Another object of our invention is to provide a dental press which embodies a pressure regulating valve and a manually operable three-way valve in series therewith, whereby the pressure at which the press is to be operated may be set and the platens operated merely by opening the manually operable valve.

A further object of our invention is to provide a dental press embodying an air cylinder which is connected with a movable platen through a compound linkage so designed as to increase, in

compact space, the pressure applied to the platen over that exerted by the piston, and at the. same time provide adequate stroke for the piston.

sclaims. (Aol. 12s-5.7)

A further object of our inventionis to provide a As is well known in the art to which our invention relates, in forming dentures from the various moldable products employed therefor, rather high pressures are required which vary with different j materials.

Presses as heretofore known to us have had their platens Xed with respect to their mountings so that if a flask was placed therebetween, uneven stresses were set up in the flask, the platens themselves, and the supporting frame Work therefor. Accordingly, it is an object of our invention to overcome these dii'l'iculties, to provide for the application of any required pressure, and to compound the motion between the cylinder and the movable platens within a compact space, thereby to permit the use of lower operating pressures within the cylinder and to provide for adequate movement of the movable platen.

Apparatus embodyingI features of our invention is illustrated in the accompanying drawing, forming a Dart of this application, in which Fig. 1 is a side elevational View of our improved press with certain parts broken away and in section;

Fig. 2 is a bottom plan View; and

Fig. 3 is a detail sectional view taken along the line III-III of Fig. 1.

Referring now to the drawing for a better understanding of our invention our improved press comprises a base I0, which may be open at thebottomto permit servicing the working parts and a top plate I I.

Mounted on the plate I I by means of studs I2 is an air cylinder I3 embodying the usual piston I4, "IUr and piston rod I6. The cylinder I3 is provided with a head I5 having a socket Il through which the piston rod I6 passes. A spring I8 surrounds the piston rod I6 and extends up into the socket I1, bearing against the upper end thereof, there- .y by to return the piston to the bottom of the cylinder I3 when pressure is relieved as will be later explained.

Pivotally connected at 2| to the upper end of the piston rod I6 is a lever 22 which is fulcrumed at 23 to a link 24, pivoted in turn, at 21, to brackets 26, fast on the cylinder I3. At its other end, the lever 22 is pivotally connected at 28 to a link 29 which passes through an enlarged opening 3I in theplate II, and is pivotally connected at its lower end beneath the plate II to a floating lever 32. The lever 32 passes through a pair of brackets 33 and 34, and is pivotally connected as at 36 to ar vertically extending pin 31. A small roller 38, journalled in the brackets 33 on a shaft 39, acts asa fulcrum for the lever 32 when pressure is applied. The' lower or movable platen 4I is carried on the upper end of the pin 31, the pin being held vertical by passing through a guide block 42 secured to the under side of the top plate I I.

Secured to the top of the plate I I are a pair of vertically extending rods 43 which are connected at their upper ends by a plate 44. Threaded through the center of the plate 44 is an adjusting bolt 46 which carries a locking nut 41.

The lower end of the bolt 46 is rounded as shown at 48 and fits within a spherical seat 49 formed in an upper platen 5 I A small pin 52 passes through a boss 53 formed on the platen 5I thereby to prevent the platen from falling off the end of the adjusting bolt 46.

The control means for the air cylinder comprises a pressure regulating valve `54 to which air under pressure is supplied through a pipe `56 from a suitable source, not shown. The pressure regulating valve 54 is provided with an adjusting wheel -51 which may be located on the outside of the machine, whereby the operating pressure of the cylinder may be adjusted or changed as required. Air under pressure from the pressure regulating valve is passed through a pipe 58 to a manually operated three way valve 59, having one outlet 60 thereof in communication with the lower end of the cylinder I3. The ex' haust outlet of the valve 59 is indicated at 6I.

To the operating connection 62 of the valve 59 is secured an operating rod $3 which projects from the front of the press and is provided with an operating handle E4.

From the foregoing the operation of our improved press 'will be readily understood. The pressure at which the cylinder is to be operated is fixed by setting the pressure regulating valve 54, the pressure being indicated by a gauge 55. It is only necessary for an operator to open the three way valve 59 by rotating the handle 64 to the proper position, whereupon air under pressure is admitted beneath the piston I 4 causing the piston to actuate the levers and raise the movable platen 4I. Conversely, when it is desired to separate the platens, pressure is released by rotating the handle 64 to the exhaust position of valve 59, whereupon spring I8 causes the -piston I4 to move downwardly.

It will be noted that the suspension point for the roller 38 is closer to the pivot point 36 than to the other pivoted end of the cross link 32, thus resulting in again compounding the motion in the linkage. In actual operation, a six inch diameter cylinder operating at 60 lb. pressure develops approximately 8,000 lbs. pressure between the platens 4I and 5I, the motion being compounded in the ratio of about to 1.

From the foregoing it will be apparent that we have devised an improved dental press which is simple and sturdy of design and economical of manufacture, and one in which the valve arrangement permits the pressure applied to the work to be varied by a simple adjustment.

While We have shown our invention in but one form, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various changes and modifications, without departing from the spirit thereof, and we desire, therefore, that only such limitations shall be placed thereupon as are specilically set forth in the appended claims.

What we claim is:

l. In a dental press, a base, an air cylinder mounted on the base, a piston and rod within the cylinder, a pressure Aregulating valve, a manually operable three-way valve interposed between the cylinder and the pressure regulating valve, a vertically movable platen, compound linkage connecting the piston rod and the Inovable platen, a pair of vertically extending rods secured to the base, a connecting plate at, the top of the rods passing over the center of the movable platen, a bolt threaded through the plate and in vertical alignment with the center of the movable platen, the lower end of said bolt being spherical, a lixed platen having a spherical seat to receive the spherical end of the bolt, and a pin loosely connecting the platen to the bolt.

2. In a dental press, a base, an air cylinder mounted on the base, a piston and rod within the cylinder, a pressure regulating valve, a manually operable three way valve interposed between the pressure regulating valve and the cylinder, a vertically movable pin projecting upwardly through the base, a lower platen fast on the upper end of said pin, compound linkage connecting the piston rod to said pin comprising upper and lower levers and links, a roller providing a fulcrum for the lower lever, a pair of vertically extending rods secured to the base, a connecting plate at the top of the rods passing over the center of the platen, a bolt threaded through the plate and in vertical alignment with the center of the platen, the lower end of the bolt being spherical, a xed upper platen having a -spherical seat to receive the spherical end of the bolt, and a pin loosely connecting the fixed platen to the spherical end of the bolt.

3. In a press, a pressure cylinder, a piston rod within the cylinder, a movable platen, an upper lever pivotally connected at one end to the piston rod, a vertically depending link connected to the other end of the upper lever, a second link connected at one end to the cylinder and at the other end to the upper lever intermediate the ends thereof, a lower lever pivotally connected at one end to the lower end of the vertically depending link, a vertically extending pin connected at its upper end to the movable platen and at its lower end to the lower lever, a roller beneath the lower lever providing an antifriction fulcrum '40'I therefor, a iixed platen, and means to adjustably support the Xed platen comprising a threaded bolt having a spherical end, a spherical seat on the platen adapted to receive the spherical end ofv the bolt, and a pin loosely connecting the platen and bolt.

JAMES C. SHARROCK. JOHN A. SHEELEY.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 2,072,694 Walter Mar. 2, 1937 2,371,547 Rosenlund Mar. 13, 1945 2,376,203 Stemmler May 15, 1945 2,150,267 Delano Mar. 14, 1939 

